Allow(unused_imports) on prelude imports
[rust-lightning] / lightning / src / ln / features.rs
index 1992b8db9e565b7696e60bc286581583ca8beed7..ff91654a3f79a33f2ed42cf9d2d4017ebde8fbae 100644 (file)
 //!     (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#basic-multi-part-payments) for more information).
 //! - `Wumbo` - requires/supports that a node create large channels. Called `option_support_large_channel` in the spec.
 //!     (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md#the-open_channel-message) for more information).
+//! - `AnchorsZeroFeeHtlcTx` - requires/supports that commitment transactions include anchor outputs
+//!     and HTLC transactions are pre-signed with zero fee (see
+//!     [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
+//!     information).
+//! - `RouteBlinding` - requires/supports that a node can relay payments over blinded paths
+//!     (see [BOLT-4](https://github.com/lightning/bolts/blob/master/04-onion-routing.md#route-blinding) for more information).
 //! - `ShutdownAnySegwit` - requires/supports that future segwit versions are allowed in `shutdown`
 //!     (see [BOLT-2](https://github.com/lightning/bolts/blob/master/02-peer-protocol.md) for more information).
 //! - `OnionMessages` - requires/supports forwarding onion messages
 //!      for more info).
 //! - `Keysend` - send funds to a node without an invoice
 //!     (see the [`Keysend` feature assignment proposal](https://github.com/lightning/bolts/issues/605#issuecomment-606679798) for more information).
-//! - `AnchorsZeroFeeHtlcTx` - requires/supports that commitment transactions include anchor outputs
-//!     and HTLC transactions are pre-signed with zero fee (see
-//!     [BOLT-3](https://github.com/lightning/bolts/blob/master/03-transactions.md) for more
-//!     information).
+//! - `Trampoline` - supports receiving and forwarding Trampoline payments
+//!     (see the [`Trampoline` feature proposal](https://github.com/lightning/bolts/pull/836) for more information).
 //!
 //! LDK knows about the following features, but does not support them:
 //! - `AnchorsNonzeroFeeHtlcTx` - the initial version of anchor outputs, which was later found to be
 //! [BOLT #9]: https://github.com/lightning/bolts/blob/master/09-features.md
 //! [messages]: crate::ln::msgs
 
-use crate::{io, io_extras};
+#[allow(unused_imports)]
 use crate::prelude::*;
+
+use crate::{io, io_extras};
 use core::{cmp, fmt};
 use core::borrow::Borrow;
 use core::hash::{Hash, Hasher};
@@ -87,6 +93,7 @@ use crate::ln::msgs::DecodeError;
 use crate::util::ser::{Readable, WithoutLength, Writeable, Writer};
 
 mod sealed {
+       #[allow(unused_imports)]
        use crate::prelude::*;
        use crate::ln::features::Features;
 
@@ -143,13 +150,15 @@ mod sealed {
                // Byte 2
                BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
                // Byte 3
-               ShutdownAnySegwit | Taproot,
+               RouteBlinding | ShutdownAnySegwit | Taproot,
                // Byte 4
                OnionMessages,
                // Byte 5
                ChannelType | SCIDPrivacy,
                // Byte 6
                ZeroConf,
+               // Byte 7
+               Trampoline,
        ]);
        define_context!(NodeContext, [
                // Byte 0
@@ -159,13 +168,15 @@ mod sealed {
                // Byte 2
                BasicMPP | Wumbo | AnchorsNonzeroFeeHtlcTx | AnchorsZeroFeeHtlcTx,
                // Byte 3
-               ShutdownAnySegwit | Taproot,
+               RouteBlinding | ShutdownAnySegwit | Taproot,
                // Byte 4
                OnionMessages,
                // Byte 5
                ChannelType | SCIDPrivacy,
                // Byte 6
                ZeroConf | Keysend,
+               // Byte 7
+               Trampoline,
        ]);
        define_context!(ChannelContext, []);
        define_context!(Bolt11InvoiceContext, [
@@ -183,6 +194,8 @@ mod sealed {
                ,
                // Byte 6
                PaymentMetadata,
+               // Byte 7
+               Trampoline,
        ]);
        define_context!(OfferContext, []);
        define_context!(InvoiceRequestContext, []);
@@ -391,6 +404,9 @@ mod sealed {
        define_feature!(23, AnchorsZeroFeeHtlcTx, [InitContext, NodeContext, ChannelTypeContext],
                "Feature flags for `option_anchors_zero_fee_htlc_tx`.", set_anchors_zero_fee_htlc_tx_optional,
                set_anchors_zero_fee_htlc_tx_required, supports_anchors_zero_fee_htlc_tx, requires_anchors_zero_fee_htlc_tx);
+       define_feature!(25, RouteBlinding, [InitContext, NodeContext],
+               "Feature flags for `option_route_blinding`.", set_route_blinding_optional,
+               set_route_blinding_required, supports_route_blinding, requires_route_blinding);
        define_feature!(27, ShutdownAnySegwit, [InitContext, NodeContext],
                "Feature flags for `opt_shutdown_anysegwit`.", set_shutdown_any_segwit_optional,
                set_shutdown_any_segwit_required, supports_shutdown_anysegwit, requires_shutdown_anysegwit);
@@ -415,6 +431,9 @@ mod sealed {
        define_feature!(55, Keysend, [NodeContext],
                "Feature flags for keysend payments.", set_keysend_optional, set_keysend_required,
                supports_keysend, requires_keysend);
+       define_feature!(57, Trampoline, [InitContext, NodeContext, Bolt11InvoiceContext],
+               "Feature flags for Trampoline routing.", set_trampoline_routing_optional, set_trampoline_routing_required,
+               supports_trampoline_routing, requires_trampoline_routing);
        // Note: update the module-level docs when a new feature bit is added!
 
        #[cfg(test)]
@@ -464,12 +483,24 @@ impl<T: sealed::Context> Clone for Features<T> {
 }
 impl<T: sealed::Context> Hash for Features<T> {
        fn hash<H: Hasher>(&self, hasher: &mut H) {
-               self.flags.hash(hasher);
+               let mut nonzero_flags = &self.flags[..];
+               while nonzero_flags.last() == Some(&0) {
+                       nonzero_flags = &nonzero_flags[..nonzero_flags.len() - 1];
+               }
+               nonzero_flags.hash(hasher);
        }
 }
 impl<T: sealed::Context> PartialEq for Features<T> {
        fn eq(&self, o: &Self) -> bool {
-               self.flags.eq(&o.flags)
+               let mut o_iter = o.flags.iter();
+               let mut self_iter = self.flags.iter();
+               loop {
+                       match (o_iter.next(), self_iter.next()) {
+                               (Some(o), Some(us)) => if o != us { return false },
+                               (Some(b), None) | (None, Some(b)) => if *b != 0 { return false },
+                               (None, None) => return true,
+                       }
+               }
        }
 }
 impl<T: sealed::Context> PartialOrd for Features<T> {
@@ -718,7 +749,11 @@ impl<T: sealed::Context> Features<T> {
                Ok(())
        }
 
-       fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
+       /// Create a [`Features`] given a set of flags, in big-endian. This is in byte order from
+       /// most on-the-wire encodings.
+       ///
+       /// This is not exported to bindings users as we don't support export across multiple T
+       pub fn from_be_bytes(mut flags: Vec<u8>) -> Features<T> {
                flags.reverse(); // Swap to little-endian
                Self {
                        flags,
@@ -798,6 +833,35 @@ impl<T: sealed::Context> Features<T> {
                true
        }
 
+       /// Sets a required feature bit. Errors if `bit` is outside the feature range as defined
+       /// by [BOLT 9].
+       ///
+       /// Note: Required bits are even. If an odd bit is given, then the corresponding even bit will
+       /// be set instead (i.e., `bit - 1`).
+       ///
+       /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
+       pub fn set_required_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+               self.set_feature_bit(bit - (bit % 2))
+       }
+
+       /// Sets an optional feature bit. Errors if `bit` is outside the feature range as defined
+       /// by [BOLT 9].
+       ///
+       /// Note: Optional bits are odd. If an even bit is given, then the corresponding odd bit will be
+       /// set instead (i.e., `bit + 1`).
+       ///
+       /// [BOLT 9]: https://github.com/lightning/bolts/blob/master/09-features.md
+       pub fn set_optional_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+               self.set_feature_bit(bit + (1 - (bit % 2)))
+       }
+
+       fn set_feature_bit(&mut self, bit: usize) -> Result<(), ()> {
+               if bit > 255 {
+                       return Err(());
+               }
+               self.set_bit(bit, false)
+       }
+
        /// Sets a required custom feature bit. Errors if `bit` is outside the custom range as defined
        /// by [bLIP 2] or if it is a known `T` feature.
        ///
@@ -824,10 +888,13 @@ impl<T: sealed::Context> Features<T> {
                if bit < 256 {
                        return Err(());
                }
+               self.set_bit(bit, true)
+       }
 
+       fn set_bit(&mut self, bit: usize, custom: bool) -> Result<(), ()> {
                let byte_offset = bit / 8;
                let mask = 1 << (bit - 8 * byte_offset);
-               if byte_offset < T::KNOWN_FEATURE_MASK.len() {
+               if byte_offset < T::KNOWN_FEATURE_MASK.len() && custom {
                        if (T::KNOWN_FEATURE_MASK[byte_offset] & mask) != 0 {
                                return Err(());
                        }
@@ -879,6 +946,13 @@ impl<T: sealed::AnchorsZeroFeeHtlcTx> Features<T> {
        }
 }
 
+impl<T: sealed::RouteBlinding> Features<T> {
+       #[cfg(test)]
+       pub(crate) fn clear_route_blinding(&mut self) {
+               <T as sealed::RouteBlinding>::clear_bits(&mut self.flags);
+       }
+}
+
 #[cfg(test)]
 impl<T: sealed::UnknownFeature> Features<T> {
        pub(crate) fn unknown() -> Self {
@@ -1017,6 +1091,7 @@ mod tests {
                init_features.set_basic_mpp_optional();
                init_features.set_wumbo_optional();
                init_features.set_anchors_zero_fee_htlc_tx_optional();
+               init_features.set_route_blinding_optional();
                init_features.set_shutdown_any_segwit_optional();
                init_features.set_onion_messages_optional();
                init_features.set_channel_type_optional();
@@ -1032,8 +1107,8 @@ mod tests {
                        // Check that the flags are as expected:
                        // - option_data_loss_protect (req)
                        // - var_onion_optin (req) | static_remote_key (req) | payment_secret(req)
-                       // - basic_mpp | wumbo | anchors_zero_fee_htlc_tx
-                       // - opt_shutdown_anysegwit
+                       // - basic_mpp | wumbo | option_anchors_zero_fee_htlc_tx
+                       // - option_route_blinding | opt_shutdown_anysegwit
                        // - onion_messages
                        // - option_channel_type | option_scid_alias
                        // - option_zeroconf
@@ -1041,7 +1116,7 @@ mod tests {
                        assert_eq!(node_features.flags[0], 0b00000001);
                        assert_eq!(node_features.flags[1], 0b01010001);
                        assert_eq!(node_features.flags[2], 0b10001010);
-                       assert_eq!(node_features.flags[3], 0b00001000);
+                       assert_eq!(node_features.flags[3], 0b00001010);
                        assert_eq!(node_features.flags[4], 0b10000000);
                        assert_eq!(node_features.flags[5], 0b10100000);
                        assert_eq!(node_features.flags[6], 0b00001000);
@@ -1078,6 +1153,13 @@ mod tests {
                assert!(!features.requires_basic_mpp());
                assert!(features.requires_payment_secret());
                assert!(features.supports_payment_secret());
+
+               // Set flags manually
+               let mut features = NodeFeatures::empty();
+               assert!(features.set_optional_feature_bit(55).is_ok());
+               assert!(features.supports_keysend());
+               assert!(features.set_optional_feature_bit(255).is_ok());
+               assert!(features.set_required_feature_bit(256).is_err());
        }
 
        #[test]
@@ -1166,4 +1248,26 @@ mod tests {
                assert!(!converted_features.supports_any_optional_bits());
                assert!(converted_features.requires_static_remote_key());
        }
+
+       #[test]
+       #[cfg(feature = "std")]
+       fn test_excess_zero_bytes_ignored() {
+               // Checks that `Hash` and `PartialEq` ignore excess zero bytes, which may appear due to
+               // feature conversion or because a peer serialized their feature poorly.
+               use std::collections::hash_map::DefaultHasher;
+               use std::hash::{Hash, Hasher};
+
+               let mut zerod_features = InitFeatures::empty();
+               zerod_features.flags = vec![0];
+               let empty_features = InitFeatures::empty();
+               assert!(empty_features.flags.is_empty());
+
+               assert_eq!(zerod_features, empty_features);
+
+               let mut zerod_hash = DefaultHasher::new();
+               zerod_features.hash(&mut zerod_hash);
+               let mut empty_hash = DefaultHasher::new();
+               empty_features.hash(&mut empty_hash);
+               assert_eq!(zerod_hash.finish(), empty_hash.finish());
+       }
 }